But where do we go from here?
We can't NOT sit, right?
In an effort to curb the potential health complications of sedentary behaviour, research has focused largely on quantifying the amount of moderate- to vigorous-intensity activity needed to be preventative on that front. Physical activity categorized as being moderate- to vigorous-intensity requires a minimum of 3 METs (METs stands for multiples of the basal metabolic rate). Anything under 3 METs has historically been considered sedentary, however this neglects the substantial health contribution of activity of a lighter-intensity. For example, standing requires the body to maintain its upright posture by isometrically contracting any and all muscles involved in maintaining the posture. This does not exceed 3 METs, however it should not be deemed as sedentary behaviour because physiological changes occur with standing such as changes in skeletal muscle LPL activity which was discussed in the first post (again, found here).
This is not to say that researching a minimum dose of moderate to vigorous activity has been in vain. For instance, a study released from the British Journal of Sports Medicine earlier this month found that even a low weekly dosage of moderate- to vigorous-intensity activity in persons aged 60 years or more have a 22% decrease in mortality risk. Higher doses of moderate- to vigorous-intensity activity further improved this reduction in mortality risk. This is great news!
*FYI, current Canadian Physical Activity Guidelines recommends adults aged 18-64 to perform a minimum of 150 minutes of moderate to vigorous activity per week, in bouts no less than 10 minutes at a time.
These minimum requirements are great idea, but is it good enough? Some research suggests otherwise. The term "active couch potato" has also been mentioned numerous times in scientific literature and various forms of social media over the last several years. People falling under this category are reaching or exceeding the minimum suggested amount of activity BUT they still spend on average 70% of their waking time performing sedentary behaviour. Despite the benefits of the recommended minimum of moderate- to vigorous-intensity activity, this level of sedentary behaviour can still compromise your metabolic health.
The same Australian study mentioned in the my first post noted that sedentary time and light-intensity time were highly negatively correlated, meaning more time spent doing light-intensity activity reduced the overall time spent being sedentary. Having a high light-intensity/sedentary ratio has been shown to reduce overall cardio-metabolic biomarkers that were mentioned earlier. Additionally, breaking up the time spent in sedentary behaviour by implementing ~2 minutes of light intensity activity (simply standing up/walking) was beneficially associated with waist circumference, body mass index, triglycerides, and blood sugar levels.
The health effects that were discussed over the last two posts addressed metabolic changes (for better or worse) to the body. Something I wrote about 6 months ago ties in nicely with all this sitting info but from a more biomechanical approach. Movement is medicine. If you're sitting for prolonged periods of time, you're probably not doing much moving which can greatly affect the integrity of your joints!
So please, at the very least complete the recommended minimum of moderate- to vigorous-intensity activity each week. But do yourself a favor and take frequent breaks to move (even a little bit) when enjoying your next Netflix marathon!